1. Field of the Invention
The present invention relates to scaffolding equipment and more particularly to a novel coordinated stage system for scaffolding equipment, pole jacks, bridges, docks and the like.
2. Prior Art
Although the present invention is suited for more general application, it is particularly adapted for use in scaffolding equipment wherein a pole jack or pump jack is raised or lowered on an upright pole to support a stage, platform or plank on which a workman or workmen can stand. The pole jack or pump jack and pole are well known to those skilled in the art and may be seen in U.S. Pat. Nos. 3,473,774 and 4,382,488. The pump jacks may be purchased from Hoitsma, Patterson, New Jersey. The pump jacks contain means which clamp on to the upright pole and include a foot pump which is utilized for raising or lowering the pump jack on the upright poles. The pump jack includes an extended arm on which can be placed the aforesaid stage, platform or plank on which a workman or workmen can stand. Generally, two pump jacks are utilized to support a single stage platform or plank; however, where the exterior of the building is of sufficient length and where three pole jacks or poles are required to be used for performing work on the building, then in that case the horizontal stages platform or planks are either placed on top of each other at the bearing ends thereof or placed in a side-by-side relationship on the pump jacks. The three pump jacks may be operated simultaneously by three separate workers or by a single worker raising or lowering each pump jack in sequence to thereby move the platform up and down the exterior of the building. The problem with this prior art arrangement of the pump jacks for stages, platforms or planks is that if the stages rest on the pump jacks in a side-by-side relationship extending the side-byside stages at the ends thereof, a serious hazard is presented since a workman concentrating on the building may fall off the end of one of the stages since the path is not in line in series and continuous. Alternatively, if the stages, platforms or planks are in a continuous path and series with one another by overlapping each other and present a step, this also presents a safety hazard since a workman may stumble over the step created by the overlapping stages, platforms or planks. Further, when three or more pump jacks or poles are utilized, it is difficult to coordinate the raising and lowering of the pump jacks or stages since the stages, platforms or planks in the prior art merely set on the pole jacks and are not connected to each other. Accordingly, there exists a pressing need for a coordinated stage system wherein two or more stages may be coupled together for use on scaffolding, pump jacks, pole jacks and the like which are safe to use, inexpensive to manufacture, may easily be uncoupled or dissambled on the pole jack or pump jack and other scaffolding equipment.